Swartchild Black Shield Clock Mainspring 6.0 x .28 mm x 13” Ref 60-28 T 33

Swartchild & Co Black Shield Clock Mainspring, HOLE End, 6.0 x 0.28 x 13”, GR Ref. 60-28 T 33, steel, new in envelope. I have several of these so the exact packaging may be different. I specialize is hard to find watch & clock parts and all parts are unconditionally guaranteed. Images do a pretty good job of representing the item